How to Keep Northern Grapevines Warm in Winter
In the cold northern regions, the protection of grapevines from the cold during winter is a crucial step to ensure a bountiful harvest the following year. As a warm-loving plant, the roots of grapevines can suffer frostbite at -6°C, and the trunk is more likely to dehydrate and die in continuously low temperatures. Scientific burial and overwintering techniques not only protect the grapevines from the cold but also regulate the soil moisture, storing energy for the spring sprouting. This article will detail the key points of overwintering protection for northern grapevines through a three-stage cold protection system.
Complete Process Analysis of Burying Grapevines in Soil for Overwintering
Precise Water Control: Frost Protection Irrigation Technique
Frost protection irrigation should follow two golden standards: timing should be completed 10-15 days before the soil freezes, and water volume should reach a penetration of 80-100 liters per plant. It is recommended to use the annular trench irrigation method, digging a circular trench 30cm deep at a distance of 50cm from the main trunk and slowly injecting water in three stages until the soil moisture content reaches over 70%. This operation can form a stable underground ice layer, effectively preventing the invasion of cold air into the roots.
Specified Stages of Soil Burying Operations
First covering of soil in early winter (when the temperature is 2°C): After the vines are taken off the trellis and bundled, cover them with 5-8cm of fine soil, focusing on protecting the grafting joints. The soil moisture at this time should be controlled between 18-22%, using moist soil that can be formed into a ball and crumbles when dropped is best.
Second reinforcing of soil (when the temperature is 0°C): Increase the thickness of soil to 60cm on top of the initial covering, extending the burial width to 2 meters. It is recommended to use a "sandwich" structure: a bottom layer of 10cm fine soil → a middle layer of 20cm straw → an upper layer of 30cm frozen soil blocks, which can increase the ground temperature by 3-5°C.
Application of Auxiliary Insulating Materials
When laying corn straw in the root area, maintain a loose thickness of 20cm, and using non-woven fabric coverage can enhance the insulation effect by 2°C. Special attention should be paid to keeping the burial radius at least 80cm away from the main trunk to avoid root damage. It is recommended to use new grapevine insulation sleeves, which are made of PE material and can be reused for 3-5 years, improving the insulation efficiency by 40% compared to traditional straw curtains.
Critical Temperature and Burying Timing
Initiate the first soil burial when the night temperature remains below -2°C for 3 consecutive days, and complete the second covering before -5°C. Different varieties have significant differences in cold resistance: The Jufeng series needs to be protected before -6°C, while the Betta rootstock grafted seedlings can tolerate temperatures as low as -8°C. It is recommended to set up soil temperature monitors in different directions of the vineyard, and the best time for soil burial is when the temperature of the 15cm soil layer drops to 3°C.
Through a three-level progressive protection system, the survival rate of northern grapevines during overwintering can reach over 98%. When spring thaws, the soil should be removed in three stages, with a 5-7 day interval between each, combined with foliar application of seaweed fertilizer, which can effectively prevent the harm of late spring cold. Scientific cold protection management can not only ensure the safety of the plants but also promote bud differentiation, laying the foundation for a bountiful harvest.